The Sex and AIDS Methodology Survey--Minority Expansion (SAMS-ME) adds an oversample of minorities (700 African American and 800 Hispanic respondents) to a recently completed project, the Sex and AIDS Methodology Survey (SAMS). The initial parent project, SAMS, is a national RDD (random digit dialing) survey of 2,030, 18 to 49 years of age in the contiguous United States that was designed to test three experiments related to methodological issues of participation bias and measurement error in telephone surveys that ask sensitive and threatening questions. This proposed minority expansion, SAMS-ME, will make possible analyses of survey error among African American and Hispanic populations heretofore neglected in methodological studies in survey research. Specifically, the SAMS-ME, which is based on the same study design as the SAMS, will involve three experiments. The first will test three household enumeration methods: the last birthday, the next birthday, and the Kish methods to determine those that increase respondent cooperation while maintaining a representative sample. The second experiment will test whether respondent control of selecting a male or female interviewer, or same versus opposite gender interviewers, will increase respondent cooperation and reduce measurement error related to questions on sexuality, abortion, and sexual abuse. The third experiment will test whether asking about sensitive information in a non judgmental context will reduce measurement error in questions on sexual behavior, abortion, and sexual abuse. Methodological studies in survey research rarely provide findings generalizable to the diversity of populations- central to demographic and epidemiological research. Without that knowledge, accurate assessment of behaviors critical to the design and implementation of effective prevention efforts are not possible. The results of this study will begin to reverse that situation by providing estimates of survey error in studies of sexuality among minority populations and by testing techniques that reduce that error.